Coal is one of the biggest sources of greenhouse gas emissions in the world. The good news is that coal\'s share of monthly power generation in the U.S. decreased to below 40 percent in November and December 2011, according to the U.S. Energy Information Administration (EIA). The last time coal\'s share of total generation fell below 40 percent for a monthly total was March 1978. The EIA attributes the decrease in coal to the increasing competitiveness of natural gas. Natural gas prices dropped \"significantly\" this winter. However, there is another contributing factor: over a hundred, 106 to be exact, coal plants closed between January 2010 and February 2012. The latest coal plants to close are in Chicago, the Fisk Plant and the Crawford Plant. The number of coal plants closed represents 162 million tons of carbon a year (nine percent of the U.S. vehicle fleet). There is more good news. Renewable energy generation is increasing, EIA data also shows. The EIA forecasts that renewable energy will account for 33 percent of the overall growth in electricity generation from 2010 to 2035. Wind power, according to the EIA, has been the fastest growing sources of new electric power generation for several years. In 2010, wind power generation increased 28.1 percent over 2009. Previous years also saw major gains: 2008 had 33.4 percent gains, 2008 had 60.7 percent gains and 2006 had 49.3 percent gains.